Cheap USB Skype/VoIP phone protocol discovery

I’ve bought cheap USB handset from eBay to use with my VoIP provider. In Widows it worked good with supplied app which supported few VoIP programs and Skype. Since I use Linux on my desktop, I tried to plug it in. In USB listing it showed up as soundcard and HID device.

Soundcard was working out of box: headset speaker and mic were correctly working when set in my linphone SIP client. But I also wanted to utilize phones keyboard and display. I checked which /dev/hidrawX device corresponds to my phone and startedsudo cat /dev/hidraw1 | hexdump. When I pressed buttons, following output has appeared:

Next mission was to make the display work. My assumption was, that it will also communicate through hidraw device. So I fired dd if=/dev/urandom of=/dev/hidraw1 and YES! Time to time the display blinked or showed some messy pixel block.

So I returned back to windows. I fired up usbsnoop to see what does the original software send to update screen. I found out, that it sends many blocks in form:
0x0301XXYYZZZZZZZZZZZZZZZZZZZZZZX’s and Y’s were incrementing independently and Z’s were apparently some data. I experimented with sending 0x0301XXYYFFFFFFFFFFFFFFFFFFFFFF with various X’s and Y’s like this: